Research on Ground Fault Monitoring Method for High Voltage Line Based on Phase Difference Method

When a ground fault occurs in the distribution network, it will cause a large-scale and long-term power outage on the entire line, which will have a significant impact on the safe and stable operation of the power system. In order to improve the real-time and accuracy of online monitoring of distribution network ground faults, a suitable ground fault monitoring method based on the phase difference detection on transmission lines is proposed. The way we detect the occurrence of ground faults is as follows: we first measure the three-phase voltage, current, and difference of their phase on the transmission line, and then we use the sudden changes of the phase difference between voltage and current as our criterion to determine whether ground faults occur or not. In order to search ground faults rapidly on the entire transmission line, it is necessary to install measurement devices at important nodes. According to the comparison of simulation tests, we find that the ground fault location judgment method based on the phase difference can detect the ground faults accurately, which is of great significance to guarantee the safety of the power supply.